Modern motor vehicles comprise a network of electromechanical actuators controlled by a central electronic control unit, or by a subsidiary control unit connected to the central one, by means of communication bus data lines. The information relative to the operation and to the actual position of the actuators are transmitted by the actuators to the central or subsidiary control unit using different protocols of communication, such a controller area network (CAN) or a local interconnecting network (LIN) data bus. The above named kind of data bus works properly but they both require expensive and complicated hardware to operate.
A different solution provides for connecting each actuator and the central, or the subsidiary, control unit through a discrete output line and for transmitting the information data, from the actuator to the control unit. According to this solution the information data are transmitted using a pulse width modulated (PWM) signal with a fixed duty cycle while coding the information data, indicative of the correct operation of the actuator, varying a frequency value of the pulse width modulated (PWM) signal. This solution has the drawback to allow the transmission of only one kind of information data for each line. As a consequence, two lines must be provided if there is the need to transmit information relating both the correct operation of the actuator and its actual position.
At least a first object is to provide a method for operating an actuator allowing the transmission of information data between a network of actuators and a central unit which does not require a complicate and expensive hardware to operate. At least a further object is to provide a method for operating an actuator allowing the transmission of information data between a network of actuators and a central unit using exactly one discrete line wherein a plurality of different information data are communicated using a single PWM signal.